<form class="form-horizontal" ng-submit="signIn()">
  <div class="form-group">
    <label for="inputEmail" ng-model="username" class="col-sm-2 control-label">用户名</label>
    <div class="col-sm-10">
      <input type="email" class="form-control" id="inputEmail3" placeholder="Email">
    </div>
  </div>
  <div class="form-group">
    <label for="inputPassword" ng-model="password" class="col-sm-2 control-label">Password</label>
    <div class="col-sm-10">
      <input type="password" class="form-control" id="inputPassword3" placeholder="Password">
    </div>
  </div>
  <div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
      <div class="checkbox">
        <label>
          <input type="checkbox"> 记住我
        </label>
      </div>
    </div>
  </div> 
  <div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
      <button type="submit" class="btn btn-default">登陆</button>  
    </div>
  </div>
</form>